The present invention relates to a combing machine with stationary detaching rollers and a reciprocating gripper which is part of the connecting rod of a linkage mechanism and is driven by a crank mounted on a gripper oscillation shaft and articulated to the lower gripper plate.
The requirements placed on a combing machine with oscillating gripper mechanism are high efficiency and good combing. In this connection, the efficiency of a combing machine is limited by the excitation of vibration arising from the intermittent operation. The magnitude of the vibration is considerably dependent on the mass acceleration forces of the oscillating gripper or a suspended pendulum gripper. The quality of the combing is dependent on the number of needles that sweep through the fiber beard. Good combing is hence only to be achieved when the path of the gripper jaw opening runs concentric to the circular comb, so that the fiber beard exit point has a small and constant distance from the needle tips of the comb segment, and a large number of needles sweep through the fiber beard.
Proposals have already been made to realize the path curve of the gripper opening required for good combing by means of an upright mounted gripper in which the lower gripper jaw is the connecting rod, or part of the connecting rod, of a four-link mechanism with a drive crank (DE-PS No. 1,161,185; DE-PS No. 1,685,601). Here, as against a suspended pendulum gripper, the oscillation path of the gripper to the detaching rollers, being half again as long and correspondingly requiring higher mass acceleration forces is disadvantageous; the position of the detaching rollers is established technologically by the path curve of the gripper opening in the phase of transfer of fiber material, and constructionally by the working region of the circular comb.
In the apparatus according to DE-PS No. 1,161,185, there further occurs an intersection of the working region of the circular comb and gripper mechanism, so that the time course of the gripper oscillation movement is positively dependent on the revolving movement and the dimensions of the circular comb. Such an intersection in fact does not occur in the combing machine disclosed in DE-PS No. 1,685,601. However, the stops provided here, for limitation of the angle which opens when the gripper swings back to a given value between the connecting rod and the link of the four-link mechanism which is pivotable about the needle tip circle, lead to a vibration excitation of the system and hence to unsteady running of the machine.
In a suspended pendulum gripper (DE-PS No. 1,685,576), the oscillation path of the gripper remains relatively short, as a result of the more favorable position of the detaching rollers which is possible here, so that the gripper accelerations and hence also the vibration excitations which influence smooth running of the machine become smaller. However, in this case there results from the path curve of the gripper opening, convex to the circular comb, a rapid lifting of the gripper from the needle tip circle, which is detrimental to good combing.